Income Taxes - Components of Income Tax Benefit (Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current tax benefit (provision):
Federal	$ 94	$ 94	$ 187
State and local	3	(39)	(26)
International	(5)	(13)	(13)
Deferred tax benefit (provision):
Federal	2,766	(1,343)	(1,226)
State and local	344	(130)	(138)
Income tax provision	$ 3,202	$ (1,431)	$ (1,216)